Sources

found: Wikipedia, Oct. 8, 2009(Short S.8 Calcutta; The Short Calcutta or S.8 was a civilian biplane airliner flying boat; introduced 1928, no. built 7; developed from Short Singapore; variants Short Rangoon)

found: Jane's Encyclopedia of Aviation, 1996:p. 801 (Short Calcutta and Rangoon, UK; the Calcutta was designed primarily for long-distance Empire sea routes; powered by 3 Bristol Jupiter XIF radial engines and accommodation for 15 passengers; from the Calcutta, Short developed the Rangoon as a long-range reconnaissance type for the RAF)